Screening of algal strains for metal removal capabilities

Eight algal species were tested for their ability to remove five toxic metals during 30-min exposures to single-metal (1 mg L-1) solutions at pH 7. Efficacy of metal bioremoval varied according to algal species and metal. Al+3 was best removed by the thermophilic blue-green alga (cyanobacterium) Mastigocladus laminosus, Hg+2 and Zn+2 by the thermophilic and acidophilic red alga Cyanidium caldarium, and Cd+2 by C. caldarium and the green alga Scenedesmus quadricauda. All of these alga/metal combinations resulted in > 90% metal removal. However, none of the eight algal species removed more than 10% of Cr+6. Results indicate that some toxic metals are more readily removed than others are by algae and that selection of appropriate strains could potentially enhance bioremoval of specific metals from wastewater at neutral pH.